The invention relates to the field of processes for treating substrates intended for the manufacture of microelectronic and/or optoelectronic components.
The invention also relates to the substrates obtained by this process.
More specifically, the invention relates to the field of processes for treating substrates that are entirely semiconductors (for example silicon) or entirely insulators, or alternatively substrates that consist of a stack of semiconducting or insulating layers. These may be substrates onto which is deposited a layer (for example an epitaxial layer) or substrates comprising nonhomogenous structures, such as substrates comprising components or parts of components at more or less advanced levels of their production.
There exists, to a certain depth from the surface of at least one face of these substrates, a layer of material which, at least partially, makes up the constitution of the components prepared on this face. This layer will be referred to hereinbelow by the expression “working layer”.
The quality of this working layer conditions that of the components. Efforts are continually being made to improve the quality of this working layer. Thus, attempts are made both to reduce the surface roughness of this working layer and to reduce the concentration of defects in the thickness of this layer.
It is known that chemical-mechanical polishing methods can be used to reduce the surface roughness of the working layer.
It is also known that chemical-mechanical polishing techniques can be used to reduce the concentration of certain defects in the working layer, when a concentration gradient of these defects exists, increasing in the direction of the surface of this layer. In this case, the chemical-mechanical polishing abrades the working layer down as far as the zones, deeper than the initial surface of the working layer, which have an acceptable concentration of these defects.
However, it is also known that chemical-mechanical polishing causes a degradation of certain properties of the working layer and a reduction in the capacity to produce substrates (FR 2 762 136 and FR 2 761 526).
It has thus been proposed to replace chemical-mechanical polishing, in particular when the working layer consists of silicon, with an annealing operation in a hydrogen-containing atmosphere (FR 2 762 136 and FR 2 761 526). An annealing, under a hydrogen-containing atmosphere, of substrates comprising a working layer consisting of silicon has an effect of reducing the surface roughness, in particular by reconstructing the silicon surface, as well as a role of healing certain crystal defects.